#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	int n = 0; 
	scanf("%d",& n);
	int arr[100000][2] = { 0 };
	int ans = 0;
	for(int i = 0;i<n;i++)
	{
		scanf("%d %d", &arr[i][0], &arr[i][1]);
	}
	int count = 0;
	for (int j = 0; j < n; j++)
	{
		for (int i = j + 1; i < n; i++)
		{
			if (arr[j][0] == arr[i][0] && arr[j][1] == arr[i][1])
			{
				count++;
				break;
			}
	    }
	}
	ans = n - count;
	printf("%d", ans);
	return 0;
}
